实现字符串的换行格式转换的源码，可以从 \r\n 到 \n 或者从 \n 到 \r\n 的转换，本程序采用类封装，并使用标准库方便移植，测试环境VS2010。-Wrap string format conversion source code, \r\n to \n or \n to \r\n conversion, the program uses a type of packaging, and the use of the standard library to faci